I keep my wild caught venezuela oscar and atabapo 1 pike at 73-74f for 5 months of the year for the last couple years with no issues. The oscar I grew from 1 inch and the pike from 6 inches. They are as aggressive as ever during feeding time.

I've had to contact Aqueon about a piece of equipment that broke as well. I really like the person who I exchanged emails with, as they were good at responding quickly, and were very nice and professional about the whole thing.

According to Lowe-Mcconnell (1999), oscars are found in rivers and pools within the Amazon basin where the temperatures range from 73f-93f.

And just like I would not want to keep them at the higher end of the extremes, I don't want to keep them at the lower end. I would consider the "extremes" (in the wild) as generally short duration events.

Water temps in the Amazon Rain Forest usually run in the 80s. I think Oscars are more comfortable in the lower to mid 80s than the lower to mid 70s;